Method of removing silicon from wrought



UNITE WV. A. OTTO WU'IH, OF PITTSBURG, PENNSYLVANIA.

METHOD OF REMOVING SILICON FROM WROUGHT-lRON.

SPECIFICATION forming part of Letters Patent No. 311,159, dated January20, 1885.

Application filed June 2, 1884. (No specimens.)

To aZZ whom it may concern:

Be it known that I, W. A. OTTO WUTH, of Pittsburg, in the county ofAllegheny and State of Pennsylvania, have invented a new and usefulImprovement in Methods of Removing Silicon from \Vrought-Iron; and I dohereby declare the following to be a full, clear, and exact descriptionthereof.

It is of great importance that the iron used in the manufacture ofcrucible and the better grades of open-hearth steel should be as free aspossible from silicon, whether chemically cent., and sometimes ashigh asfour per cent.

One per cent. of slag contains about .12 per cent. of silicon, and 2.50per cent. of slag .30 per cent. of silicon.

The iron as it comes from the furnace to be hammered into blooms orbillets, no matter by what process produced-the Catalan forge orpuddling-furnaceconsists of a spongy, pasty mass of iron the intersticesof which are filled with a fluid slag or cinder, (silicate of iron.) Theseparation of the slag from iron is accomplished by mechanical means.For the lower grades of iron, not suitable for making steel, it is doneby passing the balls through a squeezer, and in other cases byhammering. If, when the balls are at a white heat, so that the cinder islimpidlike water, the full force of the hammer could be appliedimmediately, all or nearly all of the cinder could be driven out,leaving the iron comparatively free from slag. But in practice thiscannot be done, as it would cause the iron to scatter in all directions,which would be both dangerous and wasteful. The practice, therefore, isto begin with light blows, delivered on all sides of the ball, which isfrequently turned, until the iron becomes gradually solid enough toallow the full force of the hammer to be applied. Nearly one-half of thetime necessary to reduce the ball to a solid billet or bloom is occupiedin getting it solid enough to allow of the full force of the hammer.During this process of hammering the slag becomes too pasty to becompletely separated from the iron. Just in proportion as thetemperature of the ball is allowed to become lower and the slag morepasty will the bloom or billet contain more or less slag, the silicon ofwhich in contact with the carbon in the crucible, reduced from silicicacid in the slag'to silicon, combines with the iron, and the result issteel with varying percentages of silicon. One hammer is provided forseveral furnaces, and as the balls, after being formed, cannot be keptin the furnace without oxidizing part of the iron, they often have to betaken out and kept in the air when the hammer is occupied. This allowsthem to cool before reaching the hammer, so that the iron is too solidand the slag too pasty to permit the latter to be driven out, no matterhow perfectly the hammering is'done.

My improved process of freeing the ball from the slag, and therebyobtaining a better and more regular product, is asfollows: I take theball as soon as it comes from the furnace and pass it through thesqueezer, by preference the rotary one, which makes it sufficientlysolid-to receive the full force of the hammer. Itis now too cold toenable the slag to be eliminated by hammering. I therefore take it afterit comes from the squeezer, and with or without passing it through theso-called lllllClQlOllS, by preference without, to a reverberatoryfurnace, and submit it to aneutral or but slightly-oxidizing flame, and,after bringing it to a white heat, remove it from the furnace and hammerthe now liquid Y cinder out of the porous mass of iron.

In testimony whereof I have hereunto set my hand this 29th day of May,A. D. 1884.

V. A. OTTO WVUTH.

WVhat I do claim as my invention, and desire to secure by LettersPatent, is

The improved method of removing silicate of iron from wrought-iron,which consists in passing the heated ball as it comes from the furnacethrough the squeezer, then reheating, and finally hammering it,substantially as described.

Vitnesses:

Jos. H. JAooBs, J. K. SMITH.

